Basal structures are found at the proximal ends of all cilia and flagella, but despite their ubiquitous occurrence, very little is known about their composition or their function. The basal apparatus of Chlamydomonas includes the basal bodies, two types of microtubular rootlets and three types of striated fibers. The long term goal of the proposed research is to determine the polypeptide composition of the individual components of the Chlamydomonas basal apparatus, and to determine the functions of each of these components and of the basal apparatus as a whole. The basal apparatuses of Chlamydomonas will be isolated and analyzed by one- and two-dimensional gel electrophoresis to identify the polypeptides present therein. Monoclonal antibodies specific for Chlamydomonas basal apparatus polypeptides will be produced and used to localize the antigens to the individual basal structures by means of immunofluorescent and immunocytochemical methods. These monoclonal antibodies will also be used to study the time of assembly, the intracellular movements, and the segregation during division of the various basal apparatus components. Monoclonal antibodies that specifically recognize components of the Chlamydomonas basal apparatus will be tested to determine if they also recognize components of the basal structures in other cell types including the ciliated cells of mammalian epithelial tissue; components that have been highly conserved throughout evolution are apt to have particularly important roles in basal apparatus morphogenesis or function. Selected monoclonal antibodies will be injected into cells to determine the function(s) of the antigen in mitosis, cytokinesis and/or cell morphogenesis. Lastly, antibodies that recognize the basal bodies or their associated structures will be used to determine whether their respective antigens are present in centrioles or the pericentriolar material, or if they are restricted to flagella-associated structures.